Method and apparatus for slicing foodstuffs

ABSTRACT

A method and apparatus for slicing of foodstuffs is provided that has a rotatable disc with a radial slot, a knife blade projecting above the rotatable disc, an angled chute for conveying foodstuffs, and an orifice between the chute and the rotatable disc. The orifice has a shape that decreases in width in the direction of rotation of the rotatable disc.

[0001] The present invention relates to a method and apparatus for thefrying of potato chips, and other foodstuffs, and especially to such amethod and apparatus that is compact and intended for use on demand andin a fast food outlet e.g. in shopping malls, food stores, restaurants,stadiums, amusement parks and the like.

[0002] Methods and apparatus for the manufacture of potato chips areknown. Such methods usually involve the slicing of the potato and theinsertion of the sliced potato into heated oil to effect frying of thepotato chip. The potato chip is conveyed through the oil, normally beingsubmerged for at least part of the period of time that the potato chipis in the oil, and then removed from the frying oil. In most instances,the potato chip is packaged in appropriate containers or packages andshipped for subsequent sale to the consumer. Such sale may not occur forseveral weeks or months.

[0003] The methods for the preparation of potato chips include methodsin which the temperature of the oil is varied during the process or inwhich the potato chip is pre-treated prior to being immersed in thefrying oil. Examples of such methods include the methods disclosed inU.S. Pat. Nos. 4,366,749, 4,863,750, 4,929,461, 5,137,740 and 5,580,598.

[0004] Attempts have been made to produce potato chips on a smallerscale, with the intention that the potato chips would be made availableto the consumer shortly after preparation. In particular, attempts havebeen made to provide freshly made potato chips to the consumer in fastfood outlets, using apparatus that is substantially smaller than is usedin large scale manufacturing processes for potato chips. Such a methodand apparatus is disclosed in U.S. Pat. No. 4,706,556. The method of thepatent included heat transfer bars in the bottom of the tank, or kettle,used in the frying to improve efficiency of the process, a potatowashing station and variable speed motors for both the potato slicer andthe conveyer system so that the speed of the slicer and conveyer couldbe coordinated with the volume of potato chips being processed. It isunderstood that, in practice, the apparatus of this patent providedinconsistent product, at least in part due to control mechanisms used inthe apparatus.

[0005] Apparatus for preparing potato chips is disclosed in U.S. Pat.No. 3,280,723. The apparatus includes a potato slicer having a potatochute with a smooth inner surface and side walls with a helical contourthat converge at the end of the chute. It is stated that the helicalwalls are arranged so that the curved and narrowing passage leads thepotatoes in the direction of rotation of the cutting blade.

[0006] An improved method for the manufacture of potato chips so as toprovide fresh potato chips to the consumer, especially for use in a fastfood outlet, or in other food outlets, is required. Such a method andapparatus has now been found.

[0007] Accordingly, one aspect of the present invention providesapparatus for preparing potato chips, said apparatus having a slicer forthe slicing of potatoes, means for conveying sliced potatoes through aheated oil bath and for removal of cooked potato chips from the heatedoil bath, said slicer comprising a knife blade that rotates at the lowerend of a hopper for potatoes, the knife blade being adapted to slicepotatoes, the sliced potatoes being fed to the heated bath, the speed ofrotation of the knife blade being adapted to be controlled so that theknife blade is stationary when the temperature of the oil bath is belowa pre-determined temperature, and the speed of rotation of the knifeblade being adapted to be further controlled so that the speed ofrotation increases as the temperature is increased above saidpre-determined temperature.

[0008] A further aspect of the present invention provides a method forthe preparation of potato chips in apparatus comprising a slicer for theslicing of potatoes, means for conveying sliced potatoes through aheated oil bath and for removal of cooked potato chips from the heatedoil bath, said slicer comprising a knife blade that rotates at the lowerend of a hopper for potatoes, the knife blade being adapted to slicepotatoes, the sliced potatoes being fed to the heated bath, said methodcomprising causing the knife blade to be stationary when the temperatureof the oil bath is below a predetermined temperature, rotating the knifeblade when said temperature is at or above said pre-determinedtemperature and increasing the speed of rotation of the knife blade asthe temperature is increased above said predetermined temperature.

[0009] A further aspect of the invention provides a slicer for preparingpotato chips, comprising:

[0010] a rotatable disc having a radial slot therein and a slicing bladeprojecting above the plane of the disc; and

[0011] a chute for downwardly conveying potatoes to said rotatable disc;

[0012] an orifice between said chute and said rotatable disc, saidorifice having a shape that decreases in depth in the direction ofrotation of the rotatable disc.

[0013] In a preferred embodiment of the present invention, the orificeis in an ovate shape of decreasing depth in the direction of rotation ofthe slicing blade.

[0014] In a further preferred embodiment of the slicer, the chute is atan acute angle with respect to the direction of rotation of the disc,and in particular terminates in a housing covering and conforming to thesaid ovate shape.

[0015] Another aspect of the invention provides apparatus for thepreparing of potato chips, having a potato slicer, a heated oil bath, aconveyor for the conveying of potato slices through the heated oil bathand means for the removal of cooked potato chips from the heated oilbath, in which the slicer for preparing said potato chips comprises (i)a rotatable disc having a radial slot therein and a slicing bladeprojecting above the plane of the disc; and (ii) a chute for downwardlyconveying potatoes to said rotatable disc;

[0016] an orifice between said chute and said rotatable disc, saidorifice having a shape that decreases in depth in the direction ofrotation of the rotatable disc.

[0017] In a preferred embodiment of the present invention, the orificeis in an ovate shape of decreasing depth in the direction of rotation ofthe slicing blade.

[0018] Another aspect of the invention provides a method for thepreparing of potato chips in apparatus having a potato slicer, a heatedoil bath, a conveyor for the conveying of potato slices through theheated oil bath and means for the removal of cooked potato chips fromthe heated oil bath, in which the slicer for preparing said potato chipscomprises (i) a rotatable disc having a radial slot therein and aslicing blade projecting above the plane of the disc; and (ii) a chutefor downwardly conveying potatoes to said rotatable disc;

[0019] an orifice between said chute and said rotatable disc, saidorifice having a shape that decreases in width in the direction ofrotation of the rotatable disc;

[0020] said method comprising feeding potatoes into the chute of thepotato slicer, rotating said disc having the blade extending upwardstherefrom by means of which each said potato to be sliced is urged intothe narrow end of the tear drop and sliced by said blade, submergingsaid sliced potato chip in the heated oil bath and removing said potatochip when cooked.

[0021] In a preferred embodiment of the present invention, the orificeis in an ovate shape of decreasing width in the direction of rotation ofthe rotatable disc.

[0022] A chute for downwardly conveying potatoes to said rotatable disc;

[0023] an orifice between said chute and said rotatable disc, saidorifice having a shape that decreases in width in the direction ofrotation of the rotatable disc.

[0024] In a preferred embodiment of the present invention, the orificeis in an ovate shape of decreasing width in the direction of rotation ofthe slicing blade.

[0025] In another embodiment, the chute has an elbow therein.

[0026] Another aspect of the invention provides apparatus for preparingfoodstuffs, said apparatus having means for conveying said foodstuffsthrough a heated oil bath and for removal of cooked foodstuffs from theheated oil bath, said apparatus having a hopper for the foodstuffs and aconveyor belt for feeding foodstuffs to the heated bath, the speed ofconveying of the foodstuffs being controlled so that the conveyor isstationary when the temperature of the oil bath is below apre-determined temperature, and the speed of the conveyor being furthercontrolled so that the speed increases as the temperature is increasedabove said pre-determined temperature.

[0027] A further aspect provides a method for the preparation offoodstuffs in apparatus comprising means for conveying the foodstuffsthrough a heated oil bath and for removal of cooked foodstuffs from theheated oil bath, said foodstuffs being fed to the heated bath on aconveyor, said method comprising causing the conveyor to be stationarywhen the temperature of the oil bath is below a pre-determinedtemperature, and to feed foodstuffs when said temperature is at or abovesaid pre-determined temperature and increasing the speed of conveyingthe foodstuffs as the temperature is increased above said pre-determinedtemperature.

[0028] In preferred embodiments of the invention, the foodstuffs arecorn chips or tortilla chips.

[0029] The present invention is illustrated by the mbodiments shown inthe drawings, in which:

[0030]FIG. 1 is a schematic representation of an apparatus for fryingpotato chips;

[0031]FIG. 2 is a schematic representation of the apparatus of FIG. 1through A-A;

[0032]FIG. 3 is a schematic representation of the apparatus of FIG. 1through B-B;

[0033]FIG. 4 is a schematic representation of a potato slicer;

[0034]FIG. 5 is a schematic representation of the potato slicer of FIG.4 in plan view;

[0035]FIG. 6 is a schematic representation of a feed system for cornchips, tortilla chips or the like; and

[0036]FIG. 7 is a schematic representation of a plumbing system.

[0037] Referring to FIG. 1, apparatus for the frying of potato chips isgenerally indicated by 1. Apparatus 1 has a housing 2 from which hood 3extends upwardly. Housing 2 has slicer chute 4 thereon that extendsdownwardly to slicer base 5.

[0038] It will be noted that slicer chute 4 extends upwardly from slicerbase 5 at an angle, preferably at an angle of approximately 45°,although the angle may be varied. In addition, slicer chute 4 terminatesat its upper end in chute inlet 4A, which is shown as being vertical.Such chute is referred to herein as having an elbow. Although variationmay be made in the angles, the intent is to permit a potato to beinserted into chute inlet 4A and fall down chute 4, and also to make itphysically difficult and preferably impossible to insert an arm and handinto the chute e.g. to dislodge a potato. The slicer and chute aredesigned so as to effectively eliminate any need to dislodge a potato,but if that should be necessary, the chute will need to be opened, asdescribed below. Safety switches should be located such that opening thechute automatically stops operation of the slicer and/or operation ofthe slicer must have stopped before the chute can be opened.

[0039] Slicer base 5 and slicer inlet 9 are designed to effect slicingof the potato, as discussed below. Slicer base 5 is located above slicer6, being separated therefrom by slicer inlet (orifice) 9.

[0040] Apparatus 1 has oil pan 10 that extends substantially throughoutthe length of the apparatus. It will be noted that oil pan 10 slopesdownwardly from the end at which slicer 6 is located towards the outletend, where outlet conveyor 7 extends into housing 2. Outlet conveyor 7is located within outlet conveyor chute 8.

[0041] At its lowest point, beneath conveyor 7, oil pan 10 has oil tankrecess 11 extending downwardly. Oil pan recess 11 is connected to oiloutlet pipe 12, which in turn is connected to oil filter 13. Oil filter13 is connected through filter pipe 14 to oil pump 15, and then throughpipe 16, or through an electric heat exchanger, to manifold 17. Manifold17 is located at the end of oil pan 10 under slicer 6. The surface ofoil 18 as indicated by oil surface 19, extends from oil manifold 17.Manifold 17 should be designed to provide an even flow of oil into oilpan 10, especially distributing oil across the width of oil pan 10.

[0042] A plurality of paddle wheels 20A and 20B are located betweenslicer 6 and outlet conveyor 7. First chip submerging wheel 21 andsecond chip submerging wheel 22 are located between the latter of paddlewheels 20B and outlet conveyor 7. In the drawings, three paddle wheelsare shown, which is the preferred number of paddle wheels. In addition,paddle wheel 20A is shown as having two paddles, whereas both of paddlewheels 20B have four paddles.

[0043] In operation, a potato P that has been previously washed andpeeled is inserted into slicer chute 4. Potato P falls down slicer chute4 and into slicer inlet (orifice) 9. Slicer 6 is rotated so as to slicethe potato and form a potato chip. The potato chip becomes deposited inoil 18 in oil pan 10 and is urged in a forward direction by flow of oilfrom manifold 17 through oil pan 10 towards oil pan recess 11. The flowof oil tends to occur beneath paddle wheels 20A and 20B and chipsubmerging wheels 21 and 22. Paddle wheels 20A and 20B rotate clockwise,in the view shown in FIG. 1. The slice of potato floats on the surface19 of oil 18, and comes into contact with paddle wheel 20A. The shape ofthe paddle is such that the slice of potato is urged forward, and heldin position by the paddle wheels in a controlled manner. When the sliceis released by the first paddle wheel 20A, it is accepted and retainedby the next paddle wheel 20B. As noted above, three paddle wheels 20Aand 20B are preferred, although other numbers of paddle wheels could beused, especially with the speed of rotation being adjusted andcontrolled to provide an acceptable product. The paddle wheelspreferably are adapted to be quickly disconnected for cleaning or otherpurposes.

[0044] The use of two paddles, and a spinner, on paddle wheel 20Aprovides a controlled entry of potato slices, whereas the four paddleson each of paddle wheels 20B ensure continued movement of the potatoslices. The paddle wheels also stage the product, so that there iscontrolled movement of potato chips, especially the time to move apotato chip through the apparatus, and prevent or reduce the likelihoodof a jam of potato slices between paddle wheels.

[0045] After emerging from the last paddle wheel, the slice of potato isforced under the surface of the oil by first potato chip submergingwheel 21, and then further urged under the surface of the oil by secondchip submerging wheel 22. Although the chip submerging wheels are shownin FIG. 1 as being wheels, it is preferred that the wheels be part of aflighted conveyor, especially in which the submerging wheels have a wiremesh conveyor belt thereon for conveying and submerging the potato chipsin the oil.

[0046] The potato chip is then collected and conveyed out of oil 18 byoutlet conveyor 7. Excess oil on the potato chip is drained from thepotato chip as it passes up outlet conveyor 7, with the oil running backdown outlet conveyor chute 8 and into oil pan 10.

[0047] Any particulate matter in oil 18 e.g. small pieces of potato fromthe slicing of potato P at slicer 6, tends to pass along oil pan 10 e.g.along the downward slope of the bottom of oil pan 10, and become locatedin oil pan recess 11. Oil 18 is passed from oil pan recess 11 throughoil outlet pipe 12 and filtered at filter 13. The oil is then pumped,using pump 15, though pipe 16 to manifold 17. It is understood that theoil would normally be circulated from oil. pan 10 through filter 13 andto manifold 17 even if the oil did not contain any particulate matter ordid not require cleaning for any other reason.

[0048] Oil 18 in oil pan 10 is heated by any convenient means. In theembodiment of FIG. 1, oil 18 is shown as being heated by oil heater 23,which is indicated by being in the form of a gas burner. However, it isto be understood that electrical or other heating methods may be used,including use of electric heat exchangers, provided that the temperatureof the oil may be adequately controlled.

[0049] The temperature of the oil is monitored by oil temperature probe24 which may be conveniently located in any part of the system, but isshown as being located in oil 18 at a location near manifold 17, atwhich the heated oil enters oil pan 10. In an embodiment, twotemperature probes are used e.g. at the manifold and at the outlet(discharge) from the pump. Alternate and preferred locations aredescribed below.

[0050] In a preferred embodiment of the operation of the apparatus ofthe present invention, the speed of rotation of slicer 6 is controlledand interrelated with the temperature of the oil 18 in oil pan 10. Thus,oil temperature probe 24 is connected through apparatus (not shown) inFIG. 1 to the variable speed motor (see FIG. 2) that controls the speedof rotation of slicer 6.

[0051] The speed of rotation is controlled such that the slicer does notrotate when the temperature of the oil is below a predetermined level.For instance, the control for the slicer could be set so that the slicerwould not rotate if the temperature of the oil was below 170° C. Whenthe temperature of oil 18 is increased to the predetermined temperature,slicer 6 would begin to rotate slowly and slice potato P that is inchute 4. In addition, as the temperature of oil 18 in oil pan 10increases above the predetermined temperature i.e. increases above 170°C. in the above example, the speed of rotation of slicer 6 is increasedproportionately. Conversely, if the temperature should fall below thepredetermined temperature, then slicer 6 would cease to rotate. Thus,the temperature and speed of rotation of the slicer are coordinated andcorrelated. Such correlation of the speed of slicer 6 to the temperatureof oil 18 ensures that potato slices are not placed in the oil bath ifthe temperature is below the predetermined temperature, and furtherincreases the rate of production of potato slices as the temperatureincreases above the predetermined temperature.

[0052] While the apparatus would normally have controls to permit anadjustment of the speed of rotation of the paddle wheels 20A and 20B andfirst and second chip submerging wheels 21 and 22, and there could besome correlation with the temperature of oil 18, there would normallynot be a direct correlation of speed of rotation of the paddle wheelsand temperature.

[0053] The interrelated control of the speed of rotation of slicer 6with the temperature of oil 18 in oil pan 10 facilitates control of thefrying of the potato chip so as to achieve greater consistency in thefrying of the potato chips.

[0054] It is to be understood that the predetermined temperature foroperation of the slicer may be set at any convenient temperature,particularly depending on the properties required in the fried potatochip. It is also understood that there would be a maximum temperature ofthe oil for operation of the apparatus, above which temperature theapparatus would cease to operate. Such a maximum temperature is utilizedto improve consistency of the potato chip obtained, but also provides asafety function by stopping operation of the apparatus e.g. in the eventof a failure in any part of the operation of the apparatus butespecially in the temperature control system. As an example, such amaximum temperature might be set at about 195° C. In the examples oftemperature given herein i.e. operation between temperatures of 170° C.and 195° C., a difference of 25° C., it is understood that the normalcontrol of temperatures in operation of the apparatus would besignificantly less than such a range of temperature. As an example, therange of temperature may be controlled to less than 20° C. using theapparatus of the invention.

[0055] It is also understood that the normal operation of the potatochip fryer described in FIG. 1 could be an as-required basis or as acontinuous operation. The latter is preferred. In operation on anas-required basis e.g. the potato chip fryer would be located in a mallor other fast food outlet where the demand for potato chips would varywith the frequency of the orders for the potato chips. Thus, when aperson made an order for potato chips, the required potatoes could beinserted into chute 4 and the potato chips would be made and cookedwhile the customer waited. This would ensure that the customer receivedfresh potato chips, and would receive potato chips that were hot. In acontinuous operation, the apparatus would be operated with freshly friedpotato chips waiting for receipt of an order from a customer, or with asmall inventory of packaged fresh potato chips.

[0056]FIG. 2 shows the apparatus of FIG. 1 viewed from above, along A-A.Housing 2 has hood 3 extending upwards therefrom, with chute 4 locatedon one end and outlet conveyor chute 8 located on the opposed end. Motor31 is shown extending from the side of housing 2, and is used to drivepaddle wheels 20A, 20B within the apparatus, as well as used to drivethe two submerging wheels, 21 and 22. An appropriate drive mechanism isused to drive the paddles and wheels. It is preferred that the paddlewheels rotate at a slightly slower rate than the submerging wheels, toreduce the likelihood of a jam of potato chips. It is to be understoodthat the paddles and wheels could be driven by different motors,preferably in a coordinated manner. Outlet conveyor chute 8 has outletconveyor motor 32 extending therefrom, which is used to drive outletconveyor 7.

[0057] In operation, motor 31 and conveyor motor 32 are variable speedmotors and may be operated independently i.e. at different speeds, orthe operation may be coordinated so that the rotation is the same or ina related manner. In a preferred embodiment, the operation of outletconveyor motor 32 is controlled so that the chips have sufficient timeto drain excess oil, optionally, to permit partial cooling of the chip,prior to being discharged from the apparatus. Thus, the operation ofoutlet conveyor motor 32 may be relatively independent of thetemperature of the oil.

[0058]FIG. 3 shows a vertical section of the apparatus through B-B ofFIG. 1. Oil heater 23 is located beneath oil pan 10, which contains oil18. Paddle wheel 20 extends substantially across the width of housing 2and is located at about, or slightly below, the level of oil surface 19.

[0059] Exhaust filter 33 is located above oil surface 19, substantiallyat the entrance to hood 3. In addition to exhaust filter 33, hoodentrance 34 is provided for flow of heated gases.

[0060] In operation, heated air, oil fumes and other volatile matterpasses from oil surface 19 of heated oil 18 in an upwards direction.This volatile matter passes through exhaust filter 33. It is intendedthat any entrained oil in the volatile matter be collected on exhaustfilter 33 and flow downwardly along exhaust filter 33 so as to bereturned to oil 10. Products of combustion from gas burner 23, includingambient air drawn from beneath the apparatus and which is used assupplementary air to achieve proper combustion of the gas, pass upthrough hood entrance 34 through duct 34A, and are exhausted throughhood 3. Hood 3 may be provided with air inlet 35, through which ambientair may be drawn to cool gases passing through an exhaust fan (notshown) that is used for drawing gases from the apparatus. In addition,hood 3 would be provided with an appropriate fire extinguisher system(not shown) e.g. discharge vents through which fire retardant e.g.potassium carbonate in a liquid form or carbon dioxide from a remotecylinder, could be vented rapidly in the event of a fire.

[0061] It will be understood that the volume and temperature of gaspermitted to pass through hood 3 must be controlled so that theapparatus fully complies with the pertinent government and municipalregulations with respect to exhausting of such gases. Appropriate flowdampers may be provided in the hood to control flow of gases, especiallyflow of gases from the burner and/or from oil 18.

[0062] In the event that an electric heat exchanger is used instead of agas burner, venting of products of combustion from the gas burner wouldnot be required, and alternate venting arrangements could be used.

[0063]FIG. 4 shows the chute and slicer used for the preparation of thpotato chips. Chute 4 is shown as connected to chute plate 40. Adjacentto chute plate 40, chute 4 extends forwards in the direction of rotationof slicer blade 6, forming slicer base 5. In doing so, slicer base 5forms an extended region, which preferably conforms to the shape ofslicer hole 45, more clearly shown in the plan view of FIG. 5. Chuteplate 40 is connected to plate handle 41 which pivots about plate pivot42. Located beneath chute plate 40 is slicer 6, having knife blade 43and slicer blade slot 44 therein. Slicer blade 43 and slicer blade 44are co-operatively located beneath chute 4, being beneath slicer hole(orifice) 45. In preferred embodiments, slicer blade 44 is adjustable,so that the thickness of the potato slice may be adjusted.

[0064]FIG. 5 shows a plan view of the chute shown in FIG. 4. Platehandle 41 pivots about plate pivot 42, and conveniently has handle bar46 thereon. Slicer hole 45 is shown in FIG. 5, and is located beneathchute 4, as shown in FIG. 4. While a variety of shapes of holes made beused for slicer hole 45, such shapes are generally a tapered ovateshape, e.g. pear shaped or tear drop shaped. Such shapes arecharacterized by a decreasing width in the direction of rotation ofslicer blade 6, shown in FIG. 5. In the embodiment shown in FIG. 5, theforward part of orifice 45 is rounded or otherwise curved, but morerectilinear shapes may be used. It is an important feature that theshape of orifice 45 decrease in the direction of rotation of slicerblade 6, so that a potato in chute 40 is urged forward for ease ofslicing. This prevents the potato, especially relatively small unslicedpotato parts of the potato, to roll like ball bearings at the entranceto slicer hold 45, being turned by slicer blade 6 with minimal slicingof the potato. The urging forward tends to retain the potato in aposition where it may be sliced by slicer blade 43. The end 48 oforifice 45 may be rounded or more pointed. In the preferred embodimentof the present invention, slicer hole 45 is in the shape of a tear drop,optionally a truncated tear drop or a tear drop with rounded point, forreasons discussed herein.

[0065] Although not shown in FIG. 5, a drive motor would be provided, toeffect rotation of the sheer blade. In addition, a mechanism should beprovided to reduce the speed of rotation of the slicer blade, whenrequired.

[0066] In operation, a potato P is cleaned, or less preferably peeledand cleaned, and placed into chute 4. Potato P passes, by gravity, downchute 4 to the bottom thereof. On rotation of slicer 6, knife blade 43cuts a slice from the bottom of the potato with the slice passingthrough slicer blade slot 44. Slicer hole 45 located at the bottom ofchute 4 has a tapered shape, as indicated in FIG. 5. As discussed above,the narrower or pointed end is oriented in the direction of rotation ofslicer 6, so that a potato in slicer hole 45 is urged towards the narrowend of the tear drop, becoming lodged therein to facilitate easy slicingof the potato.

[0067] Access to the slicer is achieved by applying pressure on handlebar 46, which pivots chute plate 40 upwards. Chute 40 may then becleaned, as may slicer 6. Although not shown, safety interlocks shouldbe provided to ensure that slicer 6 is not and cannot be rotated, exceptby hand, when chute plate 40 is moved upwards to open slicer 6.

[0068]FIG. 6 shows an alternate feed mechanism for the apparatus of theinvention that is particularly intended for use with other foodstuffs,especially corn chips or tortilla chips. It is intended that the feedmechanism of FIG. 6 could be located on the apparatus of the invention,at the location of the potato slicer. The potato slicer would be removedfrom the apparatus, e.g. by opening the potato slicer as described abovewith respect to FIG. 5. Typically, the potato slicer would be opened,with slicer blade being removed if necessary, and the alternate feedmechanism installed. It is particularly intended that such installationwould be easily accomplished, to facilitate rapid changes, or thealternate feed mechanism would be permanently attached to the apparatus,and could be activated on opening of the slicer. Attachments for thealternate feed mechanism are not shown in FIG. 6, but will be apparentto persons skilled in the art.

[0069] In FIG. 6, the feed mechanism, 50, has a feed conveyor 51 withhopper 52 on the upper (inlet) end thereof. Hopper 52 has feed slot 53located above feed conveyor 51, so that chips may flow from hopper 52onto conveyor 51. Conveyor 51 is driven by drive wheels 54, using amotor (not shown).

[0070] At the lower or feed end of conveyor 51 is located roller 55,which would be spaced above conveyor 51 by a distance of at least thethickness of the chips to be fed. In addition, roller 55 has tynes 56thereon. Tynes 56 would normally be formed from a soft rubbery materialso as to not damage chips contacted by the tynes. It is preferred thatthe spacing between tynes 56 and conveyor 51 be approximately thethickness of the chips, or slightly less.

[0071] In operation, corn chips or tortilla chips, or such other chipsor foodstuffs as are to be fried, are placed in hopper 52. With conveyor51 operating, the chips are fed through feed slot 53 and along conveyor51. While there may be a mono-layer of such chips, there will frequentlybe random stacking or multiple layers of chips. Tynes 56 on roller 55facilitate the feeding of a single layer of chips from the end ofconveyor 51, at which time the chips fall into oil 18 (not shown), andare processed as described above with respect to potato slices. It isunderstood that the rate of feed of corn chips, tortilla chips or suchother foodstuffs being fed to the fryer would be controlled with respectto the temperature of the oil in the same manner as described above withreference to potato slices.

[0072]FIG. 7 shows an alternate piping arrangement for use with oil pan10. Oil pan 10 is connected, to oil pan recess 11, as described abovewith respect to FIG. 1. Oil pan recess 11 is connected through pipe 60and valve 61 to pump 62. From pump 62, pipe 63 is connected tothermocouples 64 and 65 and control valve 66, through pipe 67 tomanifold 17. In addition, pump 62 is connected to drain 69 and to pipe67. Pipe 67 feeds to holding tank 68.

[0073] In operation, oil 18 is circulated from oil pan 10 through filter13 by pump 62. The oil is passed through pipes 63 and 67 to oil manifold17. In pipes 63 and 67 are located thermocouples 64 and 65, fordetermining the temperature of the oil and for detection that thetemperature has exceeded the pre-set maximum temperature. Safety valve66 is a flow switch valve installed for safety in the event that thepumping system must be shut down.

[0074] For cleaning or other reasons, oil may be discharged throughdrain 69. Alternatively, especially for cleaning of the apparatus, theoil may be pumped through pipe 67 to holding tank 68.

[0075] The heating of the oil has been particularly described withreference to the use of gas burners 23. In one alternate method ofheating the oil, the oil may be passed through a heat exchanger. In theheat exchanger, the oil may be heated directly with a heater.Alternatively, a shell and tube heat exchanger, or other types of heatexchanger, may be used to heat the oil. It is understood that any suchheat exchanger would be equipped with appropriate drainage systems. Useof an electric heat exchanger is a preferred method of heating the oil.

[0076] The present invention provide a compact apparatus, and relatedmethod, for the provision of freshly fried potato chips, corn chips,tortilla chips or other foodstuffs. The apparatus is intended for use ondemand, or continuously, and for location in fast food outlets, e.g.shopping malls, food stores, restaurants, stadiums, amusement parks andthe like. The apparatus may be controlled to provide consistency in thefresh product obtained.

1. Apparatus for preparing potato chips, said apparatus having a slicerfor the slicing of potatoes, means for conveying sliced potatoes througha heated oil bath and for removal of cooked potato chips from the heatedoil bath, said slicer comprising a knife blade that rotates at the lowerend of a hopper for potatoes, the knife blade being adapted to slicepotatoes, the sliced potatoes being fed to the heated bath, the speed ofrotation of the knife blade being adapted to be controlled so that theknife blade is stationary when the temperature of the oil bath is belowa pre-determined temperature, and the speed of rotation of the knifeblade being adapted to be further controlled so that the speed ofrotation increases as the temperature is increased above saidpre-determined temperature.
 2. The apparatus of claim 1 in which theknife blade is adapted to slice potatoes and feed each slice potatoseparately to the oil bath.
 3. The apparatus of claim 1 or claim 2 inwhich the oil is adapted to be heated using an electric heat exchanger.4. The apparatus of claim 1 or claim 2 in which the oil is adapted to beheated using gas.
 5. A method for the preparation of potato chips inapparatus comprising a slicer for the slicing of potatoes, means forconveying sliced potatoes through a heated oil bath and for removal ofcooked potato chips from the heated oil bath, said slicer comprising aknife blade that rotates at the lower end of a hopper for potatoes, theknife blade being adapted to slice potatoes, the sliced potatoes beingfed to the heated bath, said method comprising causing the knife bladeto be stationary when the temperature of the oil bath is below apre-determined temperature, rotating the knife blade when saidtemperature is at or above said pre-determined temperature andincreasing the speed of rotation of the knife blade as the temperatureis increased above said pre-determined temperature.
 6. The method ofclaim 5 in which each of said sliced potatoes is fed separately to theoil bath.
 7. The method of claim 5 in which said predeterminedtemperature is about 170° C.
 8. The method of claim 7 in which therotation of the knife blade ceases if the temperature increases to about195° C. or above.
 9. A slicer for preparing potato chips, comprising: arotatable disc having a radial slot therein and a slicing bladeprojecting above the plane of the disc; and a chute for downwardlyconveying potatoes to said rotatable disc; an orifice between said chuteand said rotatable disc, said slicer having at least one of said orificehaving a shape that decreases in width in the direction of rotation ofthe rotatable disc and said chute decreasing in depth in the directionof rotation of the rotatable disc.
 10. The slicer of claim 9 which thechute decreases in depth in the direction of rotation of the rotatabledisc.
 11. The slicer of claim 9 which the chute decreases in width inthe direction of rotation of the rotatable disc.
 12. The slicer of claim9 in which the orifice is in an ovate shape of decreasing width in thedirection of rotation of the slicing blade.
 13. The slicer of claim 9 orclaim 12 in which the chute is at an acute angle with respect to thedirection of rotation of the disc.
 14. The slicer of claim 13 in whichthe chute terminates in a housing covering and conforming to the saidovate shape.
 15. Apparatus for the preparing of potato chips, having apotato slicer, a heated oil bath, a conveyor for the conveying of potatoslices through the heated oil bath and means for the removal of cookedpotato chips from the heated oil bath, in which the slicer for preparingsaid potato chips comprises (i) a rotatable disc having a radial slottherein and a slicing blad projecting above the plane of the disc; and(ii) a chute for downwardly conveying potatoes to said rotatable disc;an orifice between said chute and said rotatable disc, said slicerhaving at least one of said orifice having a shape that decreases inwidth in the direction of rotation of the rotatable disc.
 16. Theapparatus of claim 13 in which the oil is adapted to be heated using anelectric heat exchanger.
 17. The apparatus of claim 13 in which the oilis adapted to be heated using gas.
 18. The apparatus of any one ofclaims 15-17 which the chute decreases in depth in the direction ofrotation of the rotatable disc.
 19. The apparatus of any one of claims15-18 which the orifice decreases in width in the direction of rotationof the rotatable disc.
 20. The apparatus of any one of claims 15-19 inwhich the orifice is in an ovate shape of decreasing width in thedirection of rotation of the slicing blade.
 21. The apparatus of any oneof claims 15-20 in which an orifice is located between said chute andsaid rotatable disc, said orifice having a shape that decreases in widthin the direction of rotation of the rotatable disc.
 22. The apparatus ofclaim 21 in which the chute has an elbow therein.
 23. A method for thepreparing of potato chips in apparatus having a potato slicer, a heatedoil bath, a conveyor for the conveying of potato slices through theheated oil bath and means for the removal of cooked potato chips fromthe heated oil bath, in which the slicer for preparing said potato chipscomprises (i) a rotatable disc having a radial slot therein and aslicing blade projecting above the plane of the disc; and (ii) a chutefor downwardly conveying potatoes to said rotatabl disc; an orificebetween said chute and said rotatable disc, said slicer having at leastone of said orifice having a shape that decreases in width in thedirection of rotation of the rotatable disc; and said chute decreasingin depth in the direction of rotation of the rotatable disc; said methodcomprising feeding potatoes into the chute of the potato slicer,rotating said disc having the blade extending upwards therefrom by meansof which each said potato to be sliced is urged into the narrow end ofthe tear drop and sliced by said blade, submerging said sliced potatochip in the heated oil bath and removing said potato chip when cooked.24. The method of claim 23 in which the orifice is an ovate shape ofdecreasing width in the direction of rotation of the blade.
 25. A chutefor downwardly conveying potatoes to a rotatable disc; an orificebetween said chute and said rotatable disc, said orifice having a shapethat decreases in width in the direction of rotation of the rotatabledisc.
 26. The chute of claim 25 in which the orifice is in an ovateshape of decreasing width in the direction of rotation of the slicingblade.
 27. The chute of claim 26 in which the chute has an elbowtherein.
 28. Apparatus for preparing foodstuffs, said apparatus havingmeans for conveying said foodstuffs through a heated oil bath and forremoval of cooked foodstuffs from the heated oil bath, said apparatushaving a hopper for the foodstuffs and a conveyor belt for feedingfoodstuffs to the heated bath, the speed of conveying of the foodstuffsbeing controlled so that the conveyor is stationary when the temperatureof the oil bath is below a pre-determined temperature, and the speed ofthe conveyor being further controlled so that the speed increases as thetemperature is increased above said pre-determined temperature. 29.Apparatus of claim 28 in which the foodstuffs are corn chips or tortillachips.
 30. A method for the preparation of foodstuffs in apparatuscomprising means for conveying the foodstuffs through a heated oil bathand for removal of cooked foodstuffs from the heated oil bath, saidfoodstuffs being fed to the heated bath on a conveyor, said methodcomprising causing the conveyor to be stationary when the temperature ofthe oil bath is below a pre-determined temperature, and to feedfoodstuffs when said temperature is at or above said pre-determinedtemperature and increasing the speed of conveying the foodstuffs as thetemperature is increased above said pre-determined temperature.
 31. Themethod of claim 30 in which the foodstuffs are corn chips or tortillachips.